Radon testing guides

118 articles

Radon is a radioactive gas that forms in the soil as uranium breaks down. It seeps in through foundation cracks and gaps around pipes. Insulation and a tight house hold it indoors. Years of exposure cause lung cancer, and the gas is still little known. Use the search below for the words people look up: radioactive gas, uranium, foundation, airtight home, lung cancer, becquerels.

How often to retest for radon

A report describes the house as it was during the test. New windows, a new slab opening, or a new fan all call for a new test.

Oct 25, 2026

New homes in Canada: a radon rough-in is not a test

Builders leave a rough-in so mitigation is simpler later. The number still comes from a test in the rooms you use.

Oct 25, 2026

Radon when you buy or sell a house in Canada

Measure before the listing when you have three months. A high result is fixable. An unknown result is what stalls a sale.

Oct 25, 2026

What changes the price of radon mitigation in Canada

The same fan does not cost the same in every house. The report and the foundation decide the quote.

Oct 25, 2026

How radon mitigation works in a house

The fan runs all the time. The pipe leaves above the roof. You confirm the result with a new long-term test.

Oct 25, 2026

Radon above 200 Bq/m³: what to do next

Do not panic. A result over 200 Bq/m³ is a fixable building problem, not an emergency evacuation.

Oct 25, 2026

4-day or 91-day radon test: which one decides

Use 4 days when time is short. Use 91 days to decide whether the house needs a mitigation system.

Oct 25, 2026

When to test for radon in Canada

Start a 91-day test while the house is closed and heated. Use 4 days sooner only when the deadline is short.

Oct 25, 2026

Where to place a radon test in the house

The result describes the room the detector sat in. Use the lowest lived-in room, at breathing height, out of drafts.

Oct 25, 2026